This invention relates to a flat edible food film based on collagen and to a foodstuff comprising said film.
Collagen is the generic term for a family of proteins which can be found in any multicellular organism. To date, about 20 different types of collagen have been described in literature. From the conformational standpoint this variety is the result of the combination of triple helical domains with globular, non-helical domains. As a consequence of the structural differences on the molecular level, the individual types of collagen aggregate into different macroscopic structures. Therefore, literature differentiates between a group of "fibril forming collagens" and other collagens (e.g. fibril associated collagens, collagens forming sheets, beaded filaments or anchoring fibrils).
Edible collagen films are well known in the art. They are used world-wide as edible wrappings of food like, for example, ham, poultry and fish products. The preparation of such collagen films has been described, for example, in DE 642 922 or DE 19970403. Their application as edible wrappings for food has been addressed, inter alia, in DE 19 45 527. Their use in wrapping meat products is known from U.S. Pat. No. 3,014,024 and CA-1.253.387 teaches the use of these collagen films for wrapping fish products.
Collagen films with specific additional functions and, therefore, containing functional ingredients incorporated into the basic film, are known from DE-PS 970 263 (film containing soluble colourants and/or soluble aroma components) and WO 95/17100 (collagen film with finely ground spices embedded as integral ingredients).
The collagen films mentioned above represent tools which have provided significant improvement and help in a vast variety of food manufacturing processes. However, there are still processes in food industry which, to date, must be considered unsatisfactory. One of such example is the manufacture of "Black Forest ham", a product most popular in the Canadian food market. The problematic step in the manufacturing process of Black Forest ham is the blackening of the surface of the processed meat.
At present, different blackening technologies are applied by the different manufacturers. Some use high density pine needle and pine wood smoke. This method, however, creates deposits of tar and creosote which build up in the smoke generators and houses, causing serious fire hazards. Moreover, the black coating formed on the product has a tendency to leach into the vacuum package when stored in refrigerated condition.
An effective, but for obvious reasons unpopular method, is to dip the netted hams into beef blood and bake the blood onto the hams. By the additional treatment with high density, high humidity smoke the desired black outer coating forms on the surface of these hams.
Most Canadian companies are known to use hot caramel solution to blacken their hams. However, numerous negative side effects are related with the application of this method:
in general, the hot solution is applied in refrigerated production areas causing condensation of steam and rise of temperature in such zones; PA1 as the netted hams have to be submerged completely in the hot caramel solution, the operator dipping the hams experiences discomfort to his glove protected hands. In contact with skin and nail beds the caramel acts as a colourant; PA1 after the dipping step the hams are placed on smoke racks where 50% of the caramel coating tends to drip off. This run off ends up on the floor and in the drain causing an extra load on the waste water treatment system, not to mention the expense related with this loss of caramel solution; PA1 the hot caramel solution has the tendency to migrate into the meat As a consequence, when the finished product is sliced the outer layer of the ham shows a smudgy dark half inch ring which looks anything else but attractive; and PA1 when handled by the counter staff or when in contact with other meats in the counter the black coating of the ham comes off. This causes very messy working conditions and contamination of other deli products as well as the slicing equipment. PA1 it must comply with the applicable legal food regulations; PA1 it must not get extracted from the collagen film during foodstuff processing or during storage in the vacuum package; and PA1 it must not transmit any strange sensorial properties to the final product.
In the Canadian market more than 50% of the hams are sold as half hams (cut in half after processing). However, to date there are no "Black Half Hams" available since the present manufacturing methods do not permit to market such a product. The Black Forest ham, cut in half and vacuum packed, would have the fresh cut surface spoilt with black caramel, making the product look messy.
Another technique applied to blacken a ham wrapped with an edible collagen film is to dip the netted ham into the solution of a specific kind of liquid smoke (Maillose, supplied by Red Arrows) and, in a second step, expose the product for six hours to a high humidity dense smoke. The resulting product, however, does not truly fulfil the criteria of a Black Forest ham. At best, the surface may be called "brown" or "dark greyishbrown". In addition, in the smoke cycle a huge excess of smoke must be applied which is very costly to the operator and smoking has always some environmental restrictions.
Therefore, there is a need of a simplified manufacturing process which overcomes the above-mentioned limitations in processing Black Forest ham or other foodstuffs with a black outer coating.